1. Field of the Invention
The present invention relates to a method of water repellent treatment for a pattern surface.
2. Description of the Related Art
In the fields of advanced devices such as a semiconductor device and a display panel, there is a proposal of a method involving subjecting a photosensitive material film to pattern (fine pattern) processing by a photolithography technology, and coating the fine pattern with a functional film uniformly. In particular, from the viewpoint of controlling waterproofness and wettability, there is a demand for a method of imparting water repellency to part of a member, and there is a proposal of a method involving forming a fine pattern having water repellency by a photolithography technology.
In this context, a fluorine-containing water repellent, which is typified by a perfluoroalkyl-group-containing compound, is a widely used water repellent. However, a long-chain-perfluoroalkyl-group (having a carbon number of C8 or more)-containing compound is persistent. Accordingly, there is a fear in that the long-chain-perfluoroalkyl-group-containing compound, which is typified by perfluorooctanesulfonic acid (PFOS) or perfluorooctanoic acid (PFOA), may affect the environment and the human body. Therefore, development of an alternative thereto has been widely performed. As the alternative, a perfluoropolyether-group-containing compound has been attracting attention. This compound is not biopersistent or accumulative in the environment, and exhibits high water repellency. In addition, from the viewpoint of usability, a compound containing hydrolyzable silane as an end having a reactive group has been mainly used. However, a fluorine-containing silane water repellent does not sufficiently react with a substrate when merely applied onto the substrate and heated, and sufficient durability is not obtained. In view of this, Japanese Patent Application Laid-Open No. 2007-196162 proposes a method involving forming a fluoroalkyl-group-containing silane compound, which has been hydrolyzed in the presence of a catalyst and water, into a film, thereby enhancing reactivity between the substrate and the formed film.